automotive engineering fundamentals

Automotive Engineering Fundamentals Richard Stone and Jeffrey K. Ball mAE - Internationa/ Warrendale. Pa. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or other- wise, without the prior written permission of SAE. For permission and licensing requests, contact: SAE Permissions 400 Commonwealth Drive Warrendale, PA 15096-0001 USA E-mail: permissions@sae.org Tel: 724-772-4028 Fax: 724-772-4891 Library of Congress Cataloging-in-Publication Data Stone, Richard. Automotive engineering fundamentals / Richard Stone and Jeffrey K. Ball, p. cm. Includes bibliographical references and index. ISBN 0-7680-0987-1 1. Automobiles\p=m-\Design and construction. I. Ball, Jeffrey K. II. Title. TL240.S853 2004 629.2'3\p=m-\dc22 2004041782 SAE 400 Commonwealth Drive Warrendale, PA 15096-0001 USA E-mail: CustomerService@sae.org Tel: 877-606-7323 (inside USA and Canada) 724-776-4970 (outside USA) Fax: 724-776-1615 Copyright \s=c\ 2004 Richard Stone and Jeffrey K. Ball ISBN 0-7680-0987-1 SAE Order No. R-199 Printed in the United States of America. Acknowledgments The following figures in this book first appeared in Introduction to Internal Combustion Engines, Third Edition, by Richard Stone, published by Palgrave Macmillan in 1999: Figures 2.2,2.4 through 2.7,2.9,2.10,2.12 through 2.15,2.17 through 2.20,2.23 through 2.28, and 2.30 through 2.32. Preface This book arose from a need for an automotive engineering textbook that included analysis, as well as descriptions of the hardware. Specifically, several courses in systems engineering use the automobile as a basis. Additionally, many universities are now involved in collegiate design competitions such as the SAE Mini Baja and Formula SAE competitions. This book should be helpful to such teams as an introductory text and as a source for further references. Given the broad scope of this topic, not every aspect of automotive engineering could be covered while keeping the text to a reasonable and affordable size. The book is aimed at third- to fourth-year engineering students and presupposes a certain level of engineering background. However, the courses for which this book was written are composed of engineering students from varied backgrounds to include mechanical, aeronau- tical, electrical, and astronautical engineering. Thus, certain topics that would be a review for mechanical engineering students may be an introduction to electrical engineers, and vice versa. Furthermore, because the book is aimed at students, it sometimes has been necessary to give only outline or simplified explanations. In such cases, numerous references have been made to sources of other information. Practicing engineers also should find this book useful when they need an overview of the subject, or when they are working on particular aspects of automotive engineering that are new to them. Automotive engineering draws on almost all areas of engineering: thermodynamics and com- bustion, fluid mechanics and heat transfer, mechanics, stress analysis, materials science, elec- tronics and controls, dynamics, vibrations, machine design, linkages, and so forth. However, automobiles also are subject to commercial considerations, such as economics, marketing, and sales, and these aspects are discussed as they arise. Again, to limit the scope of this project, several important automotive engineering concepts are notable for their absence. Two examples notable for their absence are manufacturing and structural design and crashworthiness. Neither of these topics was omitted because the topics were deemed unimportant. Rather, they did not fit the particular curriculum this book tar- geted. In short, topics that have been omitted are not intended to slight the importance of the topics, but choices had to be made in the scope of the text. The book has been organized to flow from the source of power (i.e., engine) through the drivetrain to the road. Chapter 1 is a brief and selective historical overview. Again, topics for Chapter 1 had to be limited to keep the scope reasonable, and the intent was to show the progression of automotive engineering over the last 100 years. Undoubtedly, readers will find several topics absent from the historical overview. Again, the absences are not intended to minimize the importance of any development, but to limit the size of Chapter 1. xiv I Automotive Engineering Fundamentals Chapter 2 contains an overview of the thermodynamic principles common to internal com- bustion engines and concludes with an extensive discussion of fuel cell principles and their systems. The differing operations of spark ignition engines and compression ignition engines are discussed in Chapters 3 and 4, respectively. Because many diesel engines now employ forced induction, the topic of turbo- and supercharging is discussed in Chapter 4 as well. Chapter 5 covers the ancillary systems associated with the engine and includes belt drives, air conditioning, and the starting and charging systems. Transmissions and drivelines are the topic of Chapter 6. This chapter includes discussion and analysis of both manual and automatic transmissions, driveshaft design, and four- and all- wheel-drive systems. The steering system is discussed in Chapter 7 and includes basic tech- niques for analyzing vehicle dynamics and rollover. The suspension system is discussed in Chapter 8, and basic models are provided as first-order analysis tools. The suspension system is another topic that is worthy of a textbook in itself, but Chapter 8 provides students and practicing engineers with several references to more detailed models and analysis techniques. Brakes and tires are the topic of Chapter 9, and Chapter 10 discusses vehicle aerodynamics. Because computer modeling is becoming increasingly important for the automotive engineer, Chapter 11 discusses matching transmissions to engines and provides a link to a computer model that is useful for predicting overall vehicle performance. Chapter 12 concludes the book with two case studies chosen to highlight the advances made in automotive engineering over the last century. The first case study is the Vauxhall 14-40, a vehicle that was studied extensively by Sir Harry Ricardo in the 1920s. As a point of comparison, the second case study is the Toyota Prius, which represents cutting-edge technology in a hybrid vehicle. The material in the book has been used by the authors in teaching an automotive systems analysis course and as part of a broad-based engineering degree course. These experiences have been invaluable in preparing this manuscript, as has been the feedback from the stu- dents. The material in the book comes from numerous sources. The published sources have been acknowledged, but of greater importance have been the conversations and discussions with colleagues and researchers involved in all areas of automotive engineering, especially when they have provided us with copies of relevant publications. We welcome criticisms or comments about the book, either concerning the details or the overall concept. Richard Stone Jeff Ball Autumn 2002 Table of Contents Preface xi11 Acknowledgments xv Chapter 1-Introduction and Overview 1 1.1 Beginnings 1 1.2 Growth and Refinement 6 1.3 Modern Development 9 1.4 Overview 16 Chapter 2 -Thermodynamics of Prime Movers 17 Introduction 17 Two- and Four-Stroke Engines 17 Indicator Diagrams and Internal Combustion Engine Performance Parameters 20 Otto and Diesel Cycle Analyses 23 2.4.1 The Ideal Air Standard Otto Cycle 24 2.4.2 The Ideal Air Standard Diesel Cycle 25 2.4.3 Efficiencies of Real Engines 30 Ignition and Combustion in Spark Ignition and Diesel Engines 32 Sources of Emissions 37 2.6.1 Simple Combustion Equilibrium 37 2.6.2 Unburned Hydrocarbons (HC) and Nitrogen Oxides (NOx) in Spark Ignition Engines 41 2.6.3 Unburned Hydrocarbons (HC), Nitrogen Oxides (NOx), and Particulates in Compression Ignition Engines 45 Fuel and Additive Requirements 45 2.7.1 Abnormal Combustion in Spark Ignition Engines 48 2.7.2 Gasoline and Diesel Additives 48 Gas Exchange Processes 50 2.8.1 Valve Flow and Volumetric Efficiency 50 2.8.2 Valve Timing 55 2.8.3 Valve Operating Systems 58 2.8.4 Dynamic Behavior of Valve Gear 60 Engine Configuration 64 2.9.1 Choosing the Number of Cylinders 64 2.9.2 Balancing of the Primary and Secondary Forces and Moments 68 2.10 Fuel Cells 79 2.10.1 Solid Polymer Fuel Cells (SPFC) 79 2.10.2 Solid Polymer Fuel Cell (SPFC) Efficiency 81 2.10.2.1 Activation Losses 83 2.10.2.2 Fuel Crossover and Internal Currents 85 2.10.2.3 Ohmic Losses 87 2.10.2.4 Mass Transfer Losses 87 2.10.2.5 Overall Response 88 2.10.3 Sources of Hydrogen for Solid Polymer Fuel Cells (SPFC) 88 2.10.3.1 Steam Reforming (SR) 89 2.10.3.2 Partial Oxidation (POX) Reforming 90 2.10.3.3 Autothermal Reforming (AR) 90 2.10.3.4 Carbon Monoxide Clean-Up and Solid Polymer Fuel Cell (SPFC) Operation on Reformed Fuel 91 2.10.3.5 Hydrogen Storage 92 2.10.4 Hydrogen Fuel Cell Systems 93 2.11 Concluding Remarks 97 2.12 Problems 97 vi Chapter 3-Spark Ignition Engines 101 3.1 Introduction 101 3.2 Spark Ignition and Ignition Timing 101 3.2.1 Ignition System Overview 101 3.2.2 The Ignition Process 105 3.2.3 Ignition Timing Selection and Control 107 3.3 Mixture Preparation 109 3.4 Combustion System Design 113 3.4.1 Port Injection Combustion Systems 113 3.4.2 Direct Injection Spark lgnition (DISI) Combustion Systems 116 3.5 Emissions Control 120 3.5.1 Development of the Three-Way Catalyst 121 3.5.2 Durability 124 3.5.3 Catalyst Light-Off 125 3.5.4 Lean-Bum NOx-Reducing Catalysts, "DENOx" 126 3.6 Power Boosting 127 3.6.1 Variable Valve Timing and Induction Tuning 127 3.6.2 Supercharging 128 3.7 Engine Management Systems 132 3.7.1 Introduction 132 3.7.2 Sensor Types 134 3.7.2.1 Crankshaft SpeedPosition and Camshaft Position 134 3.7.2.2 Throttle Position 136 3.7.2.3 Air Flow Rate 136 3.7.2.4 Inlet Manifold Absolute Pressure 137 3.7.2.5 Air Temperature and Coolant Temperature 137 3.7.2.6 Air-Fuel Ratio 137 3.7.2.7 Knock Detector 140 Automotive Engineering Fundamentals 3.8 Engine Management System Functions 142 3.8.1 Ignition Timing 142 3.8.2 Air-Fuel Ratio Control 143 3.8.3 Exhaust Gas Recirculation (EGR) Control 144 3.8.4 Additional Functions 144 3.8.5 Concluding Remarks on Engine Management Systems 146 3.9 Conclusions 147 3.10 Questions 147 Table of Contents Chapter 4-Diesel Engines 149 4.1 Introduction 149 4.2 Direct and Indirect Injection Combustion Chambers 150 4.3 Fuel Injection Equipment 152 4.3.1 Pump-Line-Injector (PLI) Systems 153 4.3.2 Electronic Unit Injectors (EUI) 155 4.3.3 Common Rail (CR) Fuel Injection Systems 156 4.4 Diesel Engine Emissions and Their Control 157 4.4.1 Diesel Engine Emissions 157 4.4.2 Diesel Engine Emissions Control 158 4.4.2.1 Exhaust Gas Recirculation (EGR) 158 4.4.2.2 Particulate Traps 159 4.5 Turbocharging 161 4.5.1 Introduction 161 4.5.2 Turbocharger Performance 164 4.5.3 Turbocharged Engine Performance 169 4.6 Diesel Engine Management Systems 172 4.7 Concluding Remarks 175 4.8 Examples 177 4.9 Problems 185 vii Chapter 5-Ancillaries 189 5.1 Introduction 189 5.2 Lubrication System 189 5.2.1 Bearings 189 . 5.2.1 1 Anti-Friction Bearings 190 5.2.1.2 Guide Bearings 190 5.2.1.3 Thrust Bearings 191 5.2.1.4 Journal Bearings 192 5.2.2 Engine Lubricants 195 5.2.3 Lubrication of Journal Bearings 197 5.3 Vehicle Cooling Systems 202 5.3.1 Coolant 206 5.4 Drive Belts 208 5.4.1 Flat Belt Drives 208 5.4.2 V-Belts 212 viii I Automotive Engineering Fundamentals 5.5 Air Conditioning Systems 213 5.5.1 Overview 213 5.5.2 Thermodynamic Performance and Operation 215 5.5.3 Coefficient of Performance (COP): 216 5.5.4 Air Conditioning System Performance 222 5.6 Generators, Motors, and Alternators 223 5.6.1 Fundamentals 223 5.6.2 Practical Alternators 227 5.6.3 Practical Starter Motors 231 5.7 Conclusions 233 Chapter 6-Transmissions and Driveline 235 6.1 Introduction 235 6.2 Friction Clutches 236 6.2.1 Torque Capability of an Axial Clutch 239 6.2.1.1 Uniform Pressure: p = pa 240 6.2.1.2 Uniform Wear 242 6.3 Gear Theory 243 6.3.1 Straight-Tooth Spur Gears 244 6.3.2 Helical Spur Gears 244 6.3.3 Straight-Tooth Bevel Gears 245 6.3.4 Spiral Bevel Gears 246 6.3.5 Hypoid Gears 246 6.4 Manual Transmissions 249 6.4.1 Transmission Power Flows 251 6.4.1.1 First Gear 251 6.4.1.2 Second Gear 251 6.4.1.3 Third Gear 252 6.4.1.4 Fourth Gear 252 6.4.1.5 Reverse 253 6.4.2 Synchronizer Operation 254 6.5 Automatic Transmissions 255 6.5.1 Fluid Couplings and Torque Converters 256 6.5.2 Planetary Gears 261 6.5.3 Planetary Gear-Set Torque Converter 265 6.5.4 Simpson Drive 267 6.5.4.1 Power Flow in First Gear 268 6.5.4.2 Power Flow in Second Gear 270 6.5.4.3 Power Flow in Third Gear 270 6.5.4.4 Power Flow in Reverse 271 6.5.5 Hydraulic Control System 272 6.6 Continuously Variable Transmissions (CVT) 275 6.6.1 Introduction 275 6.6.2 Van Doorne Continuously Variable Transmission (CVT) 275 6.6.3 Torotrak Continuously Variable Transmission (CVT) 277 6.7 Driveshafts 281 6.7.1 Hooke's Joints 281 6.7.2 Shaft Whirl 286 6.8 Differentials 290 6.9 Four-wheel Drive (FWD) and All-Wheel Drive (AWD) 293 6.9.1 Part-Time Four-wheel Drive (4WD) 294 6.9.2 On-Demand Four-wheel Drive (4WD) 295 6.9.3 Full-Time Four-wheel Drive (4WD) 295 6.9.4 All-Wheel Drive (AWD) 295 6.10 Case Study: The Chrysler 42LE Automatic Transaxle 296 6.10.1 Configuration 296 6.10.2 Planetary Gear Set 296 6.10.3 Chain Transfer Drive 299 6.10.4 Control System 299 6.11 Problems 299 Table of Contents Chapter 7-Steering Systems and Steering Dynamics 303 7.1 Introduction 303 7.2 Steering Mechanisms 303 7.2.1 Worm Systems 305 7.2.2 Worm and Sector 305 7.2.3 Worm and Roller 305 7.2.4 Recirculating Ball 307 7.2.5 Rack and Pinion Steering 308 7.2.6 Power Steering 308 7.3 Steering Dynamics 311 7.3.1 Low-Speed Turning 311 7.3.2 High-speed Turning 312 7.3.3 Effects of Tractive Forces 318 7.4 Wheel Alignment 320 7.4.1 Camber 320 7.4.2 Steering Axis Inclination (SAI) 320 7.4.3 Toe 321 7.4.4 Caster 323 7.4.5 Wheel Alignment 324 7.5 Steering Geometry Errors 324 7.6 Front-Wheel-Drive Influences 327 7.6.1 Driveline Torque 327 7.6.2 Loss of Cornering Stiffness Due to Tractive Forces 329 7.6.3 Increase in Aligning Torque Due to Tractive Forces 329 7.7 Four-wheel Steering 330 7.7.1 Low-Speed Turns 331 7.7.2 High-speed Turns 332 7.7.3 Implementation of Four-wheel Steering 333 ix [...]... Manual 1958 Porsche Speedster Four-Speed Manual I958 Ford T-Bird Three-Speed Automatic 1999 Honda Odyssey Four-Speed Automatic (set) 114 Mile (seclmp h) 16 Automotive Engineering Fundamentals 1.4 Overview The purpose of this book is to give automotive engineering students a basic understanding of the principles involved with designing a vehicle Naturally, any attempt to provide a manual for the complete,... accessories were removed, including alternators, air conditioning compressors, oil and water pumps, and so forth The Society ofAutomotive Engineers (SAE) finally stepped in with engine test standards and mandated all horsepower ratings to be given as SAE net In 10 I Automotive Engineering Fundamentals Figure 1.7 A 1955 small-block Chevrolet staged at a drag strip Courtes-v o f Mr Martin Bowe other words, the... inciting envy of the rich" (Rae, 1965) The general public's reaction also ranged to great curiosity In 1896, the Barnum and Bailey circus displayed a Duryea vehicle in its sideshow, and the 2 I Automotive Engineering Fundamentals vehicle received more attention than the usual sideshow fare of bearded ladies and so forth (May, 1975) It also is an odd fact of history that the United States had to reinvent... were disassembled, the parts were thoroughly mixed, and three cars were reassembled For this, Henry Leland and Cadillac received the Dewar Trophy, the highest award for automotive achievement (Motor Trend, 1996) 4 Azitomotive Engineering Fundamentals This period also saw the application of electrics to vehicles Several methods of ignition were used in early gasoline engines, including hot tubes and sparks... described most of the roads of the day His vehicle had a high ground clearance and a fairly flexible frame that enabled the wheels to maintain contact with the ground in rough terrain 6 / Automotive Engineering Fundamentals Finally, on January 5, 1914, Ford announced that the standard wage for a Ford worker was $5 per day, and the standard shift was reduced from 10 hours to 8 hours Ford was not being.. .Automotive Engineering Fundamentals x 7.8 7.9 Vehicle Rollover 337 7.8.1 Quasi-Static Model 337 7.8.2 Quasi-Static Rollover with Suspension 337 7.8.3 Roll Model 339 Problems ... stop the assembly line; such a prerogative rested solely with management This technique required a team of reworkers at the end of the line who would tear into the car to fix any defects 12 Automotive Engineering Fundamentals To design and produce a car in the mass production system, several different departments must work together, such as marketing, powertrain, chassis, and manufacturing Within the... for used vehicles of such size Conversely, as the price of gasoline falls, the demand for such large vehicles again rises This makes forecasting difficult for any auto manufacturer, and 14 Automotive Engineering Fundamentals [a Tax per ~ler I Gas p ~ c e ~ e r c ! u ~ per Ifler l ~a~s 1 I I Italy 1 - I Germany Japan Canada Un~ted States $0.00 50.20 $0.40 S0.80 $0.60 $1.00 $1.20 U.S Dollars Figure... Transmission Matching 11.2.1 Selecting the Engine Size and Final Drive Ratio for Maximum Speed 11.2.2 Use of Overdrive Ratios to Improve Fuel Economy 473 473 473 474 477 xii Automotive Engineering Fundamentals 11.2.3 Use of Continuously Variable Transmissions (CVT) to Improve Performance 479 11.2.4 Gearbox Span 482 11.3 Computer Modeling 486 11.3.1 Introduction... In addition to providing an overview of some of the techniques used in automotive engineering, it is hoped that the student will come away from this book with an appreciation for the automobile as a system The modern automobile is more than the sum of its parts Each subsystem must work in harmony with the others, and the modern automotive market is quick to discern vehicles that are merely a collection . when they are working on particular aspects of automotive engineering that are new to them. Automotive engineering draws on almost all areas of engineering: thermodynamics and com- bustion,. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or other- wise, without the prior written permission of SAE. For permission and licensing requests, contact: SAE Permissions 400 Commonwealth Drive Warrendale, PA 15096-0001 USA E-mail: permissions@sae.org Tel: 724-772-4028 Fax: 724-772-4891 Library of Congress Cataloging-in-Publication Data Stone, Richard. Automotive engineering fundamentals / Richard Stone and Jeffrey K. Ball, p. cm. Includes bibliographical references and index. ISBN 0-7680-0987-1 1. Automobilesp=m-Design and construction. I. Ball, Jeffrey K. II. Title. TL240.S853 2004 629.2'3p=m-dc22 2004041782 SAE 400 Commonwealth Drive Warrendale, PA 15096-0001 USA E-mail: CustomerService@sae.org Tel: 877-606-7323 (inside USA and Canada) 724-776-4970 (outside USA) Fax: 724-776-1615 Copyright s=c 2004 Richard Stone and Jeffrey K. Ball ISBN 0-7680-0987-1 SAE Order No. R-199 Printed in the United States of America. Acknowledgments. book arose from a need for an automotive engineering textbook that included analysis, as well as descriptions of the hardware. Specifically, several courses in systems engineering use the automobile